1. Field of the Invention
This invention relates to communications and tracking systems that track the location, movement, and destination of vehicles or individuals.
2. Description of Related Art
Many businesses deliver packages to customers and may have one or a fleet of vehicles for such deliveries. A nearly universal problem for these businesses is tracking and planning the movement of the delivery people and vehicles. FIG. 1 shows a tracking system similar to that described in U.S. Pat. No. 5,959,577, which is hereby incorporated by reference in its entirety. The system of FIG. 1 includes multiple mobile units (also referred to herein as rovers) 110. Each rover 110 can be a handheld device that a delivery person carries or a device mounted in a vehicle. Each rover 110 contains a global positioning system (GPS) receiver, a wireless device, and a control circuit. When activated, the GPS receiver receives signals from GPS satellites 120 and from the signal identifies the position (e.g., longitude and latitude) and velocity of a rover 110. The wireless device, typically a wireless modem, transmits the position and velocity information via a wireless network 130 and the Internet 150 to a service center 140.
Service center 140 receives and collects data from mobile units 110 and makes the collected data available to a user of a terminal 160. Terminal 160 is typically a computer that connects via the Internet 150 to a web site associated with service center 140. The user can view the data or send a query or message to service center 140 for relaying to a specific rover 110. In response to communications from terminal 160, service center 140 sends the query or message to the selected rover 110.
Although the system of FIG. 1 provides a convenient method for a business to track deliveries, the system is generally not accessible to the business' customers who may also be interested in knowing when a delivery will arrive. Additionally, the business expecting an arrival of a vehicle at a particular location such as a loading dock must periodically check the position of the vehicle to determine when the vehicle can be expected. This monitoring may be subject to errors since the vehicle while near the destination may be headed elsewhere. Accordingly, a possible improvement of the system of FIG. 1 would be to provide better information indicating expected arrival times and to provide such information not only to the business but also to customers without requiring the business or customers to constantly poll the position of the delivery vehicle.